> On pages 11 and 47 from the ADF-QMMM and 9, 42 and 139 from
>the Users Guide documentation, the property total energy is
>presented. However, page 194 of the Users Guide states that "The
>total energy is not computed.". How can I calculate the total energy with
>ADF?

I don't know exactly what is written on p. 194 of the Users Guide,
but the last statement probably means that the TOTAL BONDING ENERGY
is computed,
relative to the sum of the total fragment energies.

In the QMMM calculations, the total energy is defined as the sum of
Uqm, Umm and Uint.
The first (Uqm) is just the same as the TOTAL BONDING ENERGY defined above,
the second and third is the sum of all classical interactions in the
MM system (Umm),
or the sum of the classical interactions between the QM and MM systems (Uint).
Note that the latter two are simply added, e.g. no distinction is
made between the two.

In the output, these terms are all explicitly reported, for instance:

Summary of Bonding Energy (energy terms are taken from the energy
decomposition above)
======================================================================================

    Electrostatic Energy: -0.943080482437877
-25.6625 -591.79 -2476.06
    Kinetic Energy: 1.424576638757944
38.7647 893.94 3740.23
    Coulomb (Steric+OrbInt) Energy: -0.702854684658525
-19.1257 -441.05 -1845.34
    XC Energy: -1.368180394991067
-37.2301 -858.55 -3592.16
    QM/MM: -0.027263725242767
-0.7419 -17.11 -71.58
                                   --------------------
----------- ---------- -----------
    Total Bonding Energy: -1.616802648572290
-43.9955 -1014.56 -4244.92

The first four terms together constitute Uqm, while the sum of Umm
and Uint is given as QM/MM.
Received on 2002-02-18 21:24:32